First published online October 7, 2008
Journal of Experimental Biology 211, 3281-3286 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.021022
Two odometers in honeybees?
M. Dacke1,*,
and
M. V. Srinivasan2
1 ARC Centre for Excellence in Vision Science, Queensland Brain Institute,
University of Queensland, St Lucia, QLD 4072, Australia
2 Research School of Biological Sciences, Australian National University,
Canberra, ACT 2601, Australia
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Fig. 1. Schematic representation of the tunnels used for training foraging
honeybees. (A) Bees were trained to forage in an open tunnel, with the feeder
(F1) placed first 4 m and then 6 m (F2) down the tunnel. (B) A second group of
bees was trained to fly to a feeder (F3) placed 6 m down the tunnel fitted
with three opaque panels, each 66.6 cm long. The panels were placed 0.66, 2.0
and 3.33 m into the tunnel. The black areas represent the covered sections. By
placing the panels on top of the tunnel, the use of celestial cues for compass
orientation was made impossible in 2 m of the first 6 m of the tunnel.
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Fig. 2. Schematic representation of the tunnels used for training and testing
foraging honeybees. (A) Training tunnel. Bees were trained to forage from a
feeder (F) placed 6 m down a tunnel fitted with three opaque panels, each 66.6
cm long. The panels were placed 0.66 m, 2.0 m and 3.33 m into the tunnel. The
black areas represent the covered sections. The opaque panels prevented the
use of celestial cues for orientation in 2 m of the first 6 m of the tunnel.
(B–D) Test tunnels. In the first test (B), the opaque panels were
identical in position and size to the ones used during training. In the second
test (C), the total covering of the tunnel was decreased to 1 m. A panel with
a length of 66.6 cm was placed 0.66 m down the tunnel, and a second panel,
33.3 cm long, were placed 3.66 m down the tunnel. In the last test (D), the
bees flew with a full view of the sky along the entire length of the tunnel.
(E) In their search for food, the bees typically flew back and forth along the
test tunnel, making a number of U-turns as they searched for the missing
reward. This searching behaviour was quantified by observation and recording
of the position in the tunnel at which the bee makes the first four U-turns
(1–4).
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Fig. 3. The effect of varying the availability of celestial compass cues on the
mean waggle duration of bees returning to the hive after feeding inside a
tunnel. The bees returned from at a feeder that was positioned 4 m or 6 m into
a straight tunnel that was fully open to the sky, and then from feeding 6 m
down a tunnel where they were prevented from receiving any celestial input
during 2 m of the first 4 m of the tunnel (for details of the set-up, see
Fig. 1). Values are means
± s.d. for each experimental condition. The mean waggle duration varies
with the length of the tunnel, but not with the access to skylight cues.
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Fig. 4. The effect of celestial input on the position at which bees search for a
previously visited feeder. Honeybees were trained to find a reward at a feeder
placed 6 m into a tunnel (dotted line), with opaque panels placed on top of
the tunnel to prevent the bees from receiving any skylight input in 2 m of the
first 4 m of the tunnel (see Fig.
2A). The bees were subsequently tested in a fresh and slightly
longer tunnel that carried no reward. When tested in a tunnel with a covering
configuration identical that used during training (A), the mean searching
position at 5.9 m was not significantly different from the position of the
feeder during the training. When tested in a tunnel in which the occlusion of
the sky was decreased by 1 m compared to the training situation (B), the mean
searching position changed to 5.1 m (the spatial layout of the panels is shown
in Fig. 2C). When tested in a
fully open tunnel (C), the mean searching position, at 4.3 m, was
approximately 2 m closer to the entrance than in the training situation. The
mean searching positions in the three experiments corresponded well to the
availability of skylight cues along the flight in the tunnel and were not
significantly different from the expected search positions of 6 m (A), 5 m (B)
and 4 m (C), respectively. The arrows denote the mean searching positions and
the bars show the search distributions recorded in each test. For details of
the experimental set-up, see Fig.
2.
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© The Company of Biologists Ltd 2008
